Semiconductor device, manufacturing method, solid state image sensor, and electronic equipment

ABSTRACT

Connection pads are formed in interlayer films provided respectively in interconnection layers of a sensor substrate on which a sensor surface having pixels is formed and a signal processing substrate configured to perform signal processing on the sensor substrate to make an electrical connection between the sensor substrate and the signal processing substrate. Then, a metal oxide film is formed between the interlayer films of the sensor substrate and the signal processing substrate, between the connection pad formed on a side toward the sensor substrate and the interlayer film on a side toward the signal processing substrate, and between the connection pad formed on the side toward the signal processing substrate and the interlayer film on the side toward the sensor substrate. The present technology can be applied to a laminated-type CMOS image sensor, for example.

TECHNICAL FIELD

The present disclosure relates to a semiconductor device, amanufacturing method, a solid state image sensor, and electronicequipment, and more particularly to a semiconductor device, amanufacturing method, a solid state image sensor, and electronicequipment that can achieve further improvement in reliability.

BACKGROUND ART

Conventionally, a solid state image sensor, such as a charge coupleddevice (CCD) or a complementary metal oxide semiconductor (CMOS) imagesensor, for example, is used in electronic equipment provided with animaging function, such as a digital still camera or a digital videocamera. The solid state image sensor has pixels in which photodiodesthat perform photoelectric conversion and a plurality of transistorshave been combined, and an image is constructed on the basis of pixelsignals output from a plurality of pixels arranged on an image plane onwhich an image of a subject is produced.

Moreover, in recent years, in order to achieve size reduction and highperformance of the solid state image sensor, a laminated-type solidstate image sensor has been developed in which, on a sensor substrate onwhich pixels are formed, a signal processing substrate that performssignal processing on an image signal output from the sensor substratehas been laminated. In such a laminated-type solid state image sensor,composite bonding, such as physically connecting bonding surfaces ofwafers and electrically connecting connection pads formed on the bondingsurfaces is performed.

For example, Patent Literature 1 discloses a semiconductor device inwhich, by forming metal films entirely on bonding surfaces of twosemiconductor substrates and performing a heating treatment in a statewhere the metal films are in contact with each other, portions of themetal films in contact with an interlayer insulation layer react to forman insulation film.

CITATION LIST Patent Literature

Patent Literature 1: JP 2013-168419A

DISCLOSURE OF INVENTION Technical Problem

Meanwhile, conventionally, a misalignment may occur when bonding wafers,which results in a structure in which part of a connection pad (Cu) ofone of the wafers has been bonded to an insulation layer (SiO2) of theother wafer. In such a structure, barrier metal will not be provided atthe interface between the connection pad and the insulation layer. Thisraises a concern that copper constituting the connection pad is diffusedfrom the interface between the connection pad and the insulation layerinto the insulation layer in a later process of applying heat (such aspost bond anneal or ILD depo, for example) to cause leakage.

In addition, a low adhesion strength between the connection pad (Cu) andthe insulation layer (SiO2) raises a concern for a reduction in theoverall bonding strength (wafer bonding strength). Thus, a resistance toElectro Migration, a resistance to Stress Induced Voiding, and the likeare reduced, which causes a reduction in reliability as a whole.

The present disclosure was made in view of these circumstances, and canachieve further improvement in reliability.

Solution to Problem

A semiconductor device of an aspect of the present disclosure includes:connection pads formed in interlayer films provided respectively ininterconnection layers of a first semiconductor substrate and a secondsemiconductor substrate to make an electrical connection between thefirst semiconductor substrate and the second semiconductor substrate;and a metal oxide film formed between the interlayer films of the firstsemiconductor substrate and the second semiconductor substrate, betweenthe connection pad formed on a side toward the first semiconductorsubstrate and the interlayer film on a side toward the secondsemiconductor substrate, and between the connection pad formed on theside toward the second semiconductor substrate and the interlayer filmon the side toward the first semiconductor substrate.

In a method of manufacturing a semiconductor device of an aspect of thepresent disclosure, the semiconductor device includes connection padsformed in interlayer films provided respectively in interconnectionlayers of a first semiconductor substrate and a second semiconductorsubstrate to make an electrical connection between the firstsemiconductor substrate and the second semiconductor substrate, and ametal oxide film formed between the interlayer films of the firstsemiconductor substrate and the second semiconductor substrate, betweenthe connection pad formed on a side toward the first semiconductorsubstrate and the interlayer film on a side toward the secondsemiconductor substrate, and between the connection pad formed on theside toward the second semiconductor substrate and the interlayer filmon the side toward the first semiconductor substrate. The methodincludes the steps of: forming a metal film on at least one bondingsurface of a bonding surface including the interlayer film on the sidetoward the first semiconductor substrate and the connection pad formedin the interlayer film and a bonding surface including the interlayerfilm on the side toward the second semiconductor substrate and theconnection pad formed in the interlayer film; and by applying a heattreatment in a state where the first semiconductor substrate and thesecond semiconductor substrate are in close contact with each other withthe metal film interposed between the first semiconductor substrate andthe second semiconductor substrate, spontaneously forming the metaloxide film resulting from a reaction between the metal film and theinterlayer films.

A solid state image sensor of an aspect of the present disclosureincludes: connection pads formed in interlayer films providedrespectively in interconnection layers of a sensor substrate on which asensor surface having pixels is formed and a signal processing substrateconfigured to perform signal processing on the sensor substrate to makean electrical connection between the sensor substrate and the signalprocessing substrate; and a metal oxide film formed between theinterlayer films of the sensor substrate and the signal processingsubstrate, between the connection pad formed on a side toward the sensorsubstrate and the interlayer film on a side toward the signal processingsubstrate, and between the connection pad formed on the side toward thesignal processing substrate and the interlayer film on the side towardthe sensor substrate.

Electronic equipment of an aspect of the present disclosure includes: asolid state image sensor including connection pads formed in interlayerfilms provided respectively in interconnection layers of a sensorsubstrate on which a sensor surface having pixels is formed and a signalprocessing substrate configured to perform signal processing on thesensor substrate to make an electrical connection between the sensorsubstrate and the signal processing substrate, and a metal oxide filmformed between the interlayer films of the sensor substrate and thesignal processing substrate, between the connection pad formed on a sidetoward the sensor substrate and the interlayer film on a side toward thesignal processing substrate, and between the connection pad formed onthe side toward the signal processing substrate and the interlayer filmon the side toward the sensor substrate.

In an aspect of the present disclosure, connection pads are formed ininterlayer films provided respectively in interconnection layers of afirst semiconductor substrate (sensor substrate) and a secondsemiconductor substrate (signal processing substrate) to make anelectrical connection between the first semiconductor substrate and thesecond semiconductor substrate. In addition, a metal oxide film isformed between the interlayer films of the first semiconductor substrateand the second semiconductor substrate, between the connection padformed on a side toward the first semiconductor substrate and theinterlayer film on a side toward the second semiconductor substrate, andbetween the connection pad formed on the side toward the secondsemiconductor substrate and the interlayer film on the side toward thefirst semiconductor substrate.

Advantageous Effects of Invention

According to an aspect of the present disclosure, it is possible toachieve further improvement in reliability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an illustration showing a configuration example of anembodiment of a solid state image sensor to which the present technologyhas been applied.

FIG. 2 is an illustration describing a method of manufacturing a solidstate image sensor.

FIG. 3 is a block diagram showing a configuration example of an imagingdevice mounted on electronic equipment.

FIG. 4 is an illustration showing a usage example in which an imagesensor is used.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, a specific embodiment to which the present technology hasbeen applied will be described in detail with reference to the drawings.

FIG. 1 is an illustration showing a configuration example of anembodiment of a solid state image sensor which is a semiconductor deviceto which the present technology has been applied.

In FIG. 1, a sectional configuration example of a solid state imagesensor 11 and an enlarged portion thereof are shown.

As shown in FIG. 1, the solid state image sensor 11 is configured bylaminating a sensor substrate 13 on which a sensor surface 12 arrangedon an image plane on which an image of a subject is produced by anoptical system not shown is formed and a signal processing substrate 14attached in a manner as to support the sensor substrate 13.

In the sensor surface 12, photodiodes which are photoelectric changingunits that receive light for conversion into electric charges arearranged in a matrix form, and imaging is performed when their pixelsreceive light.

The sensor substrate 13 is configured by laminating, for example, asilicon layer in which photodiodes, transistors, and the likeconstituting pixels are formed and an interconnection layer in whichinterconnect lines to be connected to pixels are formed, and outputs animage signal of an image imaged on the sensor surface 12. For example,the interconnection layer is configured by forming a metal interconnectline having conductivity within an interlayer film 15 made of silicondioxide (SiO2).

The signal processing substrate 14 carries out various types of signalprocessing on an image signal output from the sensor substrate 13, andthen, outputs the image signal to a later-stage image processingcircuit. Moreover, the signal processing substrate 14 is provided withan interconnection layer in which an interconnect line for capturing theimage signal output from the sensor substrate 13 is formed, and thatinterconnection layer is provided with an interlayer film 16 similarlyto the interlayer film 15 of the sensor substrate 13.

In this manner, the solid state image sensor 11 is configured bylaminating the sensor substrate 13 and the signal processing substrate14, and the sensor substrate 13 and the signal processing substrate 14are bonded physically and electrically. For example, on the right sideof FIG. 1, a sectional configuration example in the vicinity of twobonding terminal portions 21-1 and 21-2 that make an electricalconnection between the sensor substrate 13 and the signal processingsubstrate 14 is shown in an enlarged manner.

In the bonding surface between the sensor substrate 13 and the signalprocessing substrate 14, a metal oxide film 22 is formed on the entiresurface except for the positions where the bonding terminal portions21-1 and 21-2 are formed.

Moreover, in the bonding terminal portion 21-1, a connection pad 23-1 isformed in which a connection pad formed on the side toward theinterlayer film 15 of the sensor substrate 13 and a connection padformed on the side toward the interlayer film 16 of the signalprocessing substrate 14 have been bonded to be integral, and anelectrical connection is made. The connection pad 23-1 is covered by abarrier metal 24 a-1 on the side toward the interlayer film 15, and theconnection pad 23-1 is covered by a barrier metal 24 b-1 on the sidetoward the interlayer film 16. Similarly, as to a connection pad 23-2formed in the bonding terminal portion 21-2, the connection pad 23-2 iscovered by a barrier metal 24 a-2 on the side toward the interlayer film15, and the connection pad 23-2 is covered by a barrier metal 24 b-2 onthe side toward the interlayer film 16.

Note that the bonding terminal portions 21-1 and 21-2 are configuredsimilarly, and hereinafter, as necessary, in a case where it is notnecessary to distinguish between the bonding terminal portions 21-1 and21-2, they will simply be referred to as a bonding terminal portion 21.Similarly, the connection pads 23-1 and 23-1 will be referred to as aconnection pad 23, the barrier metals 24 a-1 and 24 a-2 will be referredto as a barrier metal 24 a, and the barrier metals 24 b-1 and 24 b-2will be referred to as a barrier metal 24 b.

Here, when bonding the sensor substrate 13 and the signal processingsubstrate 14, an adjustment for aligning the connection pad formed inthe interlayer film 15 of the sensor substrate 13 and the connection padformed in the interlayer film 16 of the signal processing substrate 14is performed. If it is possible to fully match them in position at thattime, the connection pad 23 can be covered by the barrier metals 24 aand 24 b. However, a slight misalignment actually occurs. Therefore, asshown in FIG. 1, the connection pad 23 is formed into a shape in whichportions on the side toward the interlayer film 15 and on the sidetoward the interlayer film 16 are misaligned.

The solid state image sensor 11 is configured such that, even if such amisalignment occurs, the connection pad 23 will not be brought intodirect contact with the interlayer films 15 and 16 by forming the metaloxide film 22. That is, in the solid state image sensor 11, the metaloxide film 22 is formed between the interlayer film 15 of the sensorsubstrate 13 and the interlayer film 16 of the signal processingsubstrate 14, between the connection pad 23 formed on the side towardthe sensor substrate 13 and the interlayer film 16 of the signalprocessing substrate 14, and between the connection pad 23 formed on theside toward the signal processing substrate 14 and the interlayer film15 of the sensor substrate 13.

Due to the fact that the metal oxide film 22 formed in this mannerfunctions as a diffusion barrier, it is possible to prevent copperconstituting the connection pad 23 from diffusing into the interlayerfilm 15 or 16, and to suppress an occurrence of leakage (a short circuitbetween interconnect lines).

Moreover, it is known that an adhesion strength between copperconstituting the connection pad 23 and SiO2 constituting the interlayerfilms 15 and 16 is low. In this respect, in the solid state image sensor11, it is possible to spontaneously form the metal oxide film 22 at theinterface between the connection pad 23 and the interlayer films 15 and16 as will be described later with reference to FIG. 2, and thus, anadhesion strength can be ensured. Accordingly, the solid state imagesensor 11 can have a higher resistance to electromigration and a higherresistance to stress migration, and it is possible to attain moreimproved reliability than conventional.

Next, a step of bonding the sensor substrate 13 and the signalprocessing substrate 14 in a method of manufacturing the solid stateimage sensor 11 will be described with reference to FIG. 2.

First, before the step of bonding the sensor substrate 13 and the signalprocessing substrate 14 is performed, the connection pads 23 a and 23 bare formed in the sensor substrate 13 and the signal processingsubstrate 14, respectively, through a damascene process.

Here, a step of forming the connection pad 23 a in the interlayer film15 of the sensor substrate 13 will be described. First, an interconnectline trench is formed in silicon dioxide (SiO2) to serve as theinterlayer film 15 or an equivalent insulation film by lithography anddry etching, and the barrier metal 24 a to serve as a diffusion barrierbetween the connection pad 23 a and the interlayer film 15 is formed inthat interconnect line trench. The barrier metal 24 a can be formed bysubjecting tantalum (Ta) to physical vapor deposition (PVD), forexample.

Thereafter, a copper (copper alloy) seed layer to serve as an electrodein a plating process in a post process is formed by physical vapordeposition, for example, and then, copper is charged through the platingprocess, and excess copper is removed by chemical mechanical polishing(CMP) to fill the interconnect line trench with copper. By such a step,the connection pad 23 a is formed. In addition, the connection pad 23 bis formed in the interlayer film 16 of the signal processing substrate14 by a similar step with the barrier metal 24 b serving as a diffusionbarrier.

Then, a metal film 31 a is formed on the entire surface of theinterlayer film 15 and the connection pad 23 a. Similarly, a metal film31 b is formed on the entire surface of the interlayer film 16 and theconnection pad 23 b. At this time, the metal films 31 a and 31 b containat least one or more elements among manganese (Mn), vanadium (V),aluminum (Al), magnesium (Mg), and zirconium (Zr), and is configured bydepositing them with a thickness of about 0.1 to 10 nm.

As a metal employed as such metal films 31 a and 31 b, a metal having aproperty of reacting with SiO2 constituting the interlayer films 15 and16 in a later heat treatment to produce an oxide is selected, forexample. Accordingly, it is possible to suppress leakage that wouldoccur between the connection pads 23. That is, it is desirable to use anoxide that has an insulation property that functions as a barrier forpreventing copper diffusion and a property that is melted into copperconstituting the connection pads 23 (which does not interfere withconduction of the interface of the connection pads 23).

Accordingly, in the sensor substrate 13, the metal film 31 a is formedon the entire surface of the interlayer film 15 and the connection pad23 a, and in the signal processing substrate 14, the metal film 31 b isformed on the entire surface of the interlayer film 16 and theconnection pad 23 b, as shown at the top of FIG. 2. Then, with the metalfilm 31 a of the sensor substrate 13 and the metal film 31 b of thesignal processing substrate 14 facing each other, alignment is adjustedsuch that the connection pads 23 a and 23 b match in position.

Then, as shown in the middle of FIG. 2, a step of bringing the entiresurface of the metal film 31 a of the sensor substrate 13 and the entiresurface of the metal film 31 b of the signal processing substrate 14into close contact and bonding them such that there are no regionsprovided where they are unbonded to each other is performed. At thistime, bonding is performed with the metal film 31 formed on the entiresurface of either one of the bonding surface of the sensor substrate 13and the bonding surface of the signal processing substrate 14, forexample. Note that it is preferable to subject the metal film 31 a andthe metal film 31 b to a pretreatment through use of liquid or gascontaining hydrogen before this step is performed, in order to improvethe bonding strength by hydrogen bonding.

Thereafter, a step of applying a heat load of 400 degrees or below isperformed, for example, with the sensor substrate 13 and the signalprocessing substrate 14 remaining in close contact.

Accordingly, as shown at the bottom of FIG. 2, the metal films 31 a and31 b are melted into copper constituting the connection pads 23 a and 23b, and the metal oxide film 22 resulting from a reaction between themetal and an oxide film is formed spontaneously. That is, as the finalstructure, the metal oxide film 22 is formed between the connection pad23 and the interlayer films 15 and 16, the connection pads 23 a and 23 bare integrated, and the metal film 31 does not exist at their interface.Note that it is generally known that many metals easily undergooxidation, whilst in a case of using a metal to serve as a conventionaldiffusion barrier (tantalum, for example) for the metal films 31 a and31 b, the diffusion barrier function of tantalum will be lost throughoxidation, and therefore, element selection is important.

Through the steps as described above, the sensor substrate 13 and thesignal processing substrate 14 are bonded physically and electrically.

The solid state image sensor 11 manufactured by such a manufacturingmethod can suppress an occurrence of leakage between the connection pads23 (a short circuit between interconnect lines) due to the fact that themetal oxide film 22 functions as a diffusion barrier. Moreover, sincethe adhesion strength can be ensured by spontaneously forming the metaloxide film 22, it is possible to achieve further improvement inreliability.

Furthermore, the solid state image sensor 11 can obtain a favorableconduction property since the metal film 31 does not exist at theinterface between the connection pads 23 a and 23 b as described above.In a case of using a metal element (titanium, for example) that causesthe metal film 31 to remain at the interface between the connection pads23 a and 23 b even after the heat treatment, for example, a resistancevalue will be increased. In contrast to this, in the solid state imagesensor 11, it is possible to avoid such an increase in resistance value.Note that the element constituting the metal film 31 having been presentbetween the connection pads 23 a and 23 b is detected in the connectionpad 23.

In addition, the solid state image sensor 11 can favorably suppress anoccurrence of leakage by making the metal films 31 a and 31 b have athickness of about 0.1 to 10 nm to form the metal oxide film 22 thin.

Note that, as described with reference to FIG. 2, it is not necessary toform the metal film 31 on both of the interlayer film 15 of the sensorsubstrate 13 and the interlayer film 16 of the signal processingsubstrate 14, but the metal film 31 should only be formed on at leastone of them, and it should only be configured that the metal oxide film22 is formed reliably.

Further, as an element that can be used for the metal film 31, nickel(Ni), cobalt (Co), iron (Fe), zinc (Zn), or silver (Ag) can be usedbesides those described above. Although the Patent Literature 1, forexample, discloses a configuration example in which titanium (Ti) isused for a metal film, titanium may easily undergo oxidation, and at thesame time, is likely to form a passive state in which reactivityexhibited in a normal state has been lost, and therefore, a state inwhich the entire thin film cannot be oxidized will occur. It is notappropriate to use such a metal that is likely to form a passive statefor the metal film 31 of the solid state image sensor 11, but it issuitable to use a metal that does not form a passive state, such asmanganese, for the metal film 31 of the solid state image sensor 11.

Note that the present technology can be applied to variouslaminated-type semiconductor devices (a memory, for example) configuredby bonding wafers, for example, besides the solid state image sensor 11as described above.

Note that the solid state image sensor 11 of each embodiment asdescribed above can be applied to various types of electronic equipment,such as an imaging system, such as a digital still camera or a digitalvideo camera, a mobile phone having an imaging function, or otherequipment having an imaging function, for example.

FIG. 3 is a block diagram showing a configuration example of an imagingdevice mounted on electronic equipment.

As shown in FIG. 3, an imaging device 101 includes an optical system102, an image sensor 103, a signal processing circuit 104, a monitor105, and a memory 106, and is capable of capturing a still image and amoving image.

The optical system 102 has one or a plurality of lenses, and guidesimage light (incident light) from a subject to the image sensor 103 toproduce an image on a light receiving surface (sensor portion) of theimage sensor 103.

As the image sensor 103, the solid state image sensor 11 of theabove-described embodiment is applied. In the image sensor 103,electrons are accumulated for a certain period of time in accordancewith an image produced on the light receiving surface via the opticalsystem 102. Then, a signal in accordance with electrons accumulated inthe image sensor 103 is supplied to the signal processing circuit 104.

The signal processing circuit 104 carries out various types of signalprocessing on a pixel signal output from the image sensor 103. An image(image data) obtained by the signal processing circuit 104 carrying outsignal processing is supplied to the monitor 105 for display, orsupplied to the memory 106 for storage (recording).

The imaging device 101 configured in this manner can improve durabilitymore and can perform imaging reliably, for example, by applying thesolid state image sensor 11 of the above-described embodiment.

FIG. 4 is an illustration showing a usage example in which theabove-described solid state image sensor 11 (image sensor) is used.

The above-described image sensor can be used for, for example, variouscases in which light such as visible light, infrared light, ultravioletlight, or X-rays is detected as follows.

-   -   Devices that take images used for viewing, such as a digital        camera and a portable appliance with a camera function.    -   Devices used for traffic, such as an in-vehicle sensor that        takes images of the front and the back of a car, surroundings,        the inside of the car, and the like, a monitoring camera that        monitors travelling vehicles and roads, and a distance sensor        that measures distances between vehicles and the like, which are        used for safe driving (e.g., automatic stop), recognition of the        condition of a driver, and the like.    -   Devices used for home electrical appliances, such as a TV, a        refrigerator, and an air conditioner, to takes images of a        gesture of a user and perform appliance operation in accordance        with the gesture.    -   Devices used for medical care and health care, such as an        endoscope and a device that performs angiography by reception of        infrared light.    -   Devices used for security, such as a monitoring camera for crime        prevention and a camera for personal authentication.    -   Devices used for beauty care, such as skin measurement equipment        that takes images of the skin and a microscope that takes images        of the scalp.    -   Devices used for sports, such as an action camera and a wearable        camera for sports and the like.    -   Devices used for agriculture, such as a camera for monitoring        the condition of the field and crops.

Additionally, the present technology may also be configured as below.

(1)

A semiconductor device including:

connection pads formed in interlayer films provided respectively ininterconnection layers of a first semiconductor substrate and a secondsemiconductor substrate to make an electrical connection between thefirst semiconductor substrate and the second semiconductor substrate;and

a metal oxide film formed between the interlayer films of the firstsemiconductor substrate and the second semiconductor substrate, betweenthe connection pad formed on a side toward the first semiconductorsubstrate and the interlayer film on a side toward the secondsemiconductor substrate, and between the connection pad formed on theside toward the second semiconductor substrate and the interlayer filmon the side toward the first semiconductor substrate.

(2)

The semiconductor device according to (1), in which

a metal film is formed on at least one bonding surface of a bondingsurface including the interlayer film on the side toward the firstsemiconductor substrate and the connection pad formed in the interlayerfilm and a bonding surface including the interlayer film on the sidetoward the second semiconductor substrate and the connection pad formedin the interlayer film, and

by applying a heat treatment in a state where the first semiconductorsubstrate and the second semiconductor substrate are in close contactwith each other with the metal film interposed between the firstsemiconductor substrate and the second semiconductor substrate, themetal oxide film resulting from a reaction between the metal film andthe interlayer films is formed spontaneously.

(3)

The semiconductor device according to (2), in which

the metal film is composed of a metal having a property in which, in theheat treatment, a portion interposed between the connection pad formedon the side toward the first semiconductor substrate and the connectionpad formed on the side toward the second semiconductor substrate ismelted into the connection pads.

(4)

The semiconductor device according to (2) or (3), in which

the metal film is composed of a metal having a property of reacting withthe interlayer films in the heat treatment to form an oxide having aninsulation property.

(5)

The semiconductor device according to any one of (2) to (4), in which

the metal film contains at least one or more elements among manganese,vanadium, aluminum, magnesium, and zirconium.

(6)

The semiconductor device according to any one of (2) to (5), in which

the metal film is formed so as to have a thickness ranging from 0.1 nmto 10 nm.

(7)

The semiconductor device according to any one of (2) to (6), in which

a pretreatment through use of liquid or gas containing hydrogen isperformed on the metal film in a state where the metal film has beenformed on the entire surface of the interlayer films and the connectionpads.

(8)

The semiconductor device according to any one of (2) to (7), in which

when bonding the first semiconductor substrate and the secondsemiconductor substrate, bonding is performed in a state where the metalfilm has been formed on the entire surface of at least one of thebonding surfaces.

(9)

A method of manufacturing a semiconductor device, in which

the semiconductor device includes

-   -   connection pads formed in interlayer films provided respectively        in interconnection layers of a first semiconductor substrate and        a second semiconductor substrate to make an electrical        connection between the first semiconductor substrate and the        second semiconductor substrate, and    -   a metal oxide film formed between the interlayer films of the        first semiconductor substrate and the second semiconductor        substrate, between the connection pad formed on a side toward        the first semiconductor substrate and the interlayer film on a        side toward the second semiconductor substrate, and between the        connection pad formed on the side toward the second        semiconductor substrate and the interlayer film on the side        toward the first semiconductor substrate,

the method including the steps of:

forming a metal film on at least one bonding surface of a bondingsurface including the interlayer film on the side toward the firstsemiconductor substrate and the connection pad formed in the interlayerfilm and a bonding surface including the interlayer film on the sidetoward the second semiconductor substrate and the connection pad formedin the interlayer film; and

by applying a heat treatment in a state where the first semiconductorsubstrate and the second semiconductor substrate are in close contactwith each other with the metal film interposed between the firstsemiconductor substrate and the second semiconductor substrate,spontaneously forming the metal oxide film resulting from a reactionbetween the metal film and the interlayer films.

(10)

A solid state image sensor including:

connection pads formed in interlayer films provided respectively ininterconnection layers of a sensor substrate on which a sensor surfacehaving pixels is formed and a signal processing substrate configured toperform signal processing on the sensor substrate to make an electricalconnection between the sensor substrate and the signal processingsubstrate; and

a metal oxide film formed between the interlayer films of the sensorsubstrate and the signal processing substrate, between the connectionpad formed on a side toward the sensor substrate and the interlayer filmon a side toward the signal processing substrate, and between theconnection pad formed on the side toward the signal processing substrateand the interlayer film on the side toward the sensor substrate.

(11)

Electronic equipment including:

a solid state image sensor including

-   -   connection pads formed in interlayer films provided respectively        in interconnection layers of a sensor substrate on which a        sensor surface having pixels is formed and a signal processing        substrate configured to perform signal processing on the sensor        substrate to make an electrical connection between the sensor        substrate and the signal processing substrate, and    -   a metal oxide film formed between the interlayer films of the        sensor substrate and the signal processing substrate, between        the connection pad formed on a side toward the sensor substrate        and the interlayer film on a side toward the signal processing        substrate, and between the connection pad formed on the side        toward the signal processing substrate and the interlayer film        on the side toward the sensor substrate.

In addition, embodiments of the present disclosure are not limited tothe above-described embodiments, and various alterations may occurinsofar as they are within the scope of the present disclosure.

REFERENCE SIGNS LIST

-   11 solid state image sensor-   12 sensor surface-   13 sensor substrate-   14 signal processing substrate-   15, 16 interlayer film-   21 bonding terminal portion-   22 metal oxide film-   23 connection pad-   24 barrier metal-   31 metal film

1-11. (canceled)
 12. A semiconductor device comprising: a sensorsubstrate including a photodiode, a transistor, and a first wiringlayer; and a circuit substrate including a signal processing circuit anda second wiring layer, the sensor substrate being stacked on the circuitsubstrate, wherein the first wiring layer includes a first connectionpad and a first insulating film, wherein the second wiring layerincludes a second connection pad and a second insulating film, wherein afirst portion of a first barrier metal contacts a first portion of thesecond connection pad, wherein a first portion of the first connectionpad contacts a second portion of the second connection pad, wherein asecond portion of the first connection pad contacts a first portion of abarrier film, wherein a second portion of the first barrier metalcontacts a second portion of the barrier film, and wherein the firstportion of the first barrier metal and the second portion of the firstbarrier metal are on opposite sides of the first connection pad.
 13. Thesemiconductor device according to claim 12, wherein, in a crosssectional view, a third portion of the barrier film is disposed betweenand contacts a first portion of the first insulating film and a firstportion of the second insulating film.
 14. The semiconductor deviceaccording to claim 12, wherein the barrier film includes an insulator.15. The semiconductor device according to claim 12, wherein the firstconnection pad and the second connection pad are disposed in aperipheral region other than a pixel region that includes thephotodiode, wherein the peripheral region surrounds the pixel region.16. The semiconductor device according to claim 12, wherein the firstand second connection pads are rectangular in a cross sectional view.17. The semiconductor device according to claim 12, wherein the barrierfilm has a thickness ranging from 0.1 nm to 10 nm.
 18. The semiconductordevice according to claim 12, wherein the first barrier metal coversthree sides of the first connection pad in a cross sectional view. 19.The semiconductor device according to claim 12, wherein a second barriermetal covers three sides of the second connection pad in a crosssectional view.
 20. The semiconductor device according to claim 12,wherein a pixel signal from the photodiode is transferred to the signalprocessing circuit via the first connection pad and the secondconnection pad.
 21. The device according to claim 12, wherein the sensorsubstrate and the circuit substrate are stacked such that the firstwiring layer and the second wiring layer face each other.
 22. Thesemiconductor device according to claim 12, wherein a silicon layer ofthe sensor substrate includes the photodiode and the silicon layer isstacked on the first wiring layer.
 23. The semiconductor deviceaccording to claim 12, wherein the first connection pad is at leastpartially covered by the first barrier metal on a side of the firstconnection pad furthest from the second insulating film.
 24. Thesemiconductor device according to claim 12, wherein the secondconnection pad is at least partially covered by a second barrier metalon a side of the second connection pad furthest from the firstinsulating film.
 25. The semiconductor device according to claim 24,wherein the second barrier metal covers at least one additional side ofthe second connection pad.
 26. The semiconductor device according toclaim 12, the first barrier metal covers at least one side of the firstconnection pad.
 27. The semiconductor device according to claim 12,wherein the barrier film includes a metal insulator.
 28. Thesemiconductor device according to claim 12, wherein the first barriermetal and the second barrier metal include Ta.
 29. The semiconductordevice according to claim 12, wherein the first connection pad and thesecond connection pad include Cu.
 30. A light detecting device,comprising: a sensor substrate including a photodiode, a transistor, anda first wiring layer; and a circuit substrate including a signalprocessing circuit and a second wiring layer, the sensor substrate beingstacked on the circuit substrate, wherein the first wiring layerincludes a first connection pad disposed in a surface of a firstinsulating film, wherein the second wiring layer includes a secondconnection pad disposed in a surface of a second insulating film,wherein a first portion of a first barrier metal contacts a firstportion of the second connection pad, wherein a first portion of thefirst connection pad contacts a second portion of the second connectionpad, wherein a second portion of the first connection pad contacts afirst portion of a barrier film, wherein a second portion of the firstbarrier metal contacts a second portion of the barrier film, wherein athird portion of the barrier film is disposed between a part of thesurface of the first insulating film and a part of the surface of thesecond insulating film, and wherein the first portion of the firstbarrier metal and the second portion of the first barrier metal are onopposite sides of the first connection pad.
 31. A vehicle sensor,comprising: a sensor substrate including a photodiode, a transistor, anda first wiring layer; and a circuit substrate including a signalprocessing circuit and a second wiring layer, the sensor substrate beingstacked on the circuit substrate, wherein the first wiring layerincludes a first connection pad disposed in a surface of a firstinsulating film, wherein the second wiring layer includes a secondconnection pad disposed in a surface of a second insulating film,wherein a first portion of a first barrier metal contacts a firstportion of the second connection pad, wherein a first portion of thefirst connection pad contacts a second portion of the second connectionpad, wherein a second portion of the first connection pad contacts afirst portion of a barrier film, wherein a second portion of the firstbarrier metal contacts a second portion of the barrier film, wherein athird portion of the barrier film is disposed between a part of thesurface of the first insulating film and a part of the surface of thesecond insulating film, and wherein the first portion of the firstbarrier metal and the second portion of the first barrier metal are onopposite sides of the first connection pad.